Shrinkage Stoping

shrinkage stoping

[′shriŋ·kij ‚stōp·iŋ]
(mining engineering)
A modification of overhead stoping, involving the use of a part of the ore for the purpose of support and as a working platform. Also known as back stoping.

Shrinkage Stoping

 

periodic filling of a worked-out space with ore broken out from the main body during underground mining of a deposit. The filling takes place as a result of blasting of ore from the rock mass. The accumulated ore serves as a platform for the miners working in the stope (stoping block) and, to a certain extent, prevents exfoliation of the enclosing rock. The enclosing rock is supported by means of interchamber and interfloor pillars of ore, unexcavated ore-free sections, and the broken mass, if it is raised after working out the reserves of the block. To reduce losses when using shrinkage stoping systems for the extraction of a valuable mineral from thin beds, the cutting is done without drift and entry pillars, replacing them with stulls and other types of support. Upon completion of stoping in the block, the accumulated ore is emptied completely.

In addition to the conventional shrinkage stoping system, when the broken ore (mineral) fills the worked-out space to the full height of the block (or level), there is also a version of the system with partial shrinkage stoping, in which the broken ore fills the worked-out space for only part of the height of the block (bed or sublevel).

The shrinkage stoping method is most suitable for lode deposits 0.5 to 4-5 m thick with persistent bedding and an angle of not less than 60°, which are represented by hard, stableores and stable enclosing rock. In the case of very thick beds, the shrinkage stoping system can be used only at an extremely steep dip angle (85°-90°).

REFERENCE

Agoshkov, M. I., S. S. Borisov, and V. A. Boiarskii. Razrabotka rudnykh i nerudnykh mestorozhdenii, 2nd ed. Moscow, 1970.

A. S. VORONIUK

References in periodicals archive ?
The ore bodies will be accessed by 2m x 2m drives and cross-cuts into stopes that are mined by traditional overhand shrinkage stoping mining methods, with the ore being drawn from access points and transported on underground locos and tipped into bins on an ore pass system.
The feasibility study proposes shrinkage stoping for mining the West Reef.
Preliminary efforts to use longhole retreat mining instead of the previous method of shrinkage stoping have increased production rate by 40 per cent, providing additional hope that costs can be further reduced.
During drawing of ore, hang-up and dilution may occur as experienced in Vertical Crater Retreat stoping or shrinkage stoping.
The thicker, richer gold intercepts in the flattened zone may be amenable to lower cost, modern mechanized mining methods as compared to the shrinkage stoping carried out historically in the steeper portions of the veins.
The PEA replaces a June 2013 feasibility study and adopts a nonmechanized shrinkage stoping mining method in place of the feasibility study's mechanized cut and fill.
Effectively a combination of long hole open stoping and shrinkage stoping, the so-called creeping cone method controls ore dilution where weak hanging wall and footwall conditions prevail.
Preliminary rock mechanics evaluation by Rock Engineering International (REI) and Call & Nicholas, Tucson AZ, (supported by laboratory testing at the University of Arizona) has confirmed to The Winters Company (TWC), Tucson AZ, the suitability of Mechanized Shrinkage Stoping as a primary underground mining method and TWC is proceeding with detailed underground mine design and production scheduling.
Our flag-ship property is Roy Lloyd [and] is targeted with 100 mt/d to 150 mt/d through the mining methods of long holing and shrinkage stoping, producing up to 15 g/mt material over the next two to three years.
Production in the CLZ is undertaken using overhand shrinkage stoping with ore drawn from the stopes using box-holes.
Efficient longhole stoping will be utilized to extract 75 per cent of the ore with mining widths up to 30 meters, while shrinkage stoping will be applied for the 25 per cent of reserves contained in narrower zones.
Preferred mining methods suggested in the feasibility are long-hole stoping, supplemented by shrinkage stoping in the narrower parts of the deposit.